Rosas, Juan Manuel de

Argentine soldier, gaucho (cowboy), and dictator 1835–52. Rosas used his private gaucho army to overthrow the Liberal regime of Bernardino Rivadavia in 1827. A Buenos Aires Federalist, he was governor of that city 1829–32 and, when he was also dictator of Argentina, presided over a reign of terror. While appealing to the urban masses, he allowed huge land sales at absurdly low prices that benefited the landed aristocracy, including Rosas's wealthy Creole family.

A manipulative and ruthless operator against centralists, once he became dictator, he began a cult of personality which included his image being displayed on church altars. Rosas supported the Uruguayan Blancos led by Manuel Oribe (1792–1857) by besieging Montevideo for nine years from 1843. This led to his downfall when a key aide, Justo José de Urquiza, changed sides and relieved the city 1852. Rosas spent the rest of his life in Britain.